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Several countries are already talking about a fourth dose of vaccine against Covid-19 for their population. In the United States, an important advisory group of experts met yesterday to find out if an adaptation of the vaccine to the latest variants is necessary.
Are we moving towards a fourth dose of the Covid-19 vaccine for all? If yes, with which vaccine? To answer this question, the United States chose to work with a group of experts from the Food and Drug Administration (FDA – the American health agency), in order to know whether this dose should be adapted to the Omicron variant.
A group of independent experts to advise the FDA
The Vaccines and Related Biologicals Advisory Committee is an independent group of experts who advise the FDA on vaccine-related matters. It met yesterday to discuss the question of the fourth dose and more particularly its adaptation. Objective: to know if the Americans will have a booster dose directed against the Omicron variant this fall.
For a vaccine specifically directed against Omicron
At the question “Does the committee recommend the inclusion of a Sars-CoV-2 Omicron component for Covid-19 booster vaccines in the United States?“, 19 of the 21 members answered “yes” and only two in the negative.
The committee therefore felt that a modified vaccine would provide broader protection to match the strain of coronavirus currently in circulation.
Towards a fourth dose for all?
However, these experts were not asked about the change in the vaccine itself, in particular on the question of the strain of the virus to be included.
Either way, this new booster will be a fourth dose for Americans and a fifth for those over 50 and the immunocompromised. While paradoxically, the population seems less worried about the pandemic and overall, vaccine demand has dropped in the country.
Dr. Gérald Kierzek, for his part, believes that “this fourth dose only makes sense for the most fragile: people with comorbidity (illness, obesity, etc.) or the elderly”.
Efficiency displayed by the laboratories
In parallel with this meeting, the Pfizer-BioNTech and Moderna laboratories shared their data demonstrating “effectiveness of their updated vaccines against the highly infectious strain of the virus”. At Pfizer-BioNTech, the data concerns 1,200 people who received two doses of vaccines plus a booster. The fourth dose shows a “significant increase in effective antibodies against Omicron” in these volunteers.
For Dr. Ugur Sahin, CEO and co-founder of BioNTech, a German company that has partnered with Pfizer for the development and manufacture of these vaccines: “The data demonstrates the ability of our Omicron-adapted monovalent and bivalent vaccine candidates to significantly enhance variant-specific antibody neutralization responses.” Similar data was unveiled by the Moderna laboratory a few weeks ago.
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A dose that saves lives?
A study by Israeli researchers and published in the scientific journal JAMA shows that the “fourth dose saved lives and reduced the need for hospitalization”. It was carried out on a cohort of 24,088 patients living in a long-term geriatric healthcare facility.
The researchers compared data from the medical records of these patients with those of 19,687 participants who received only three doses, at least four months previously. They found that the 4th dose provided 34% protection against infection, 64-67% against acute hospitalizations and 72% against death.